The primary structure of regweed allergen antigen E will be determined. From this information, it will be possible to fragment this molecule and isolate various component peptides. These will be tested to see which fragments retain and are responsible for IgE reactivity to this allergen. Those fragments responsible for T cell sensitization will also be sought. The long range goal of this project is to attempt to identify large fragments of antigen E which do not react with IgE and are therefore useful immunogens for desensitization therapy via the production of other classes of antibody.